PROJECT SUMMARY: The treatment of children with heart failure, secondary to acquired or congenital heart disease, is a formidable challenge for clinicians. Heart transplantation, when available, becomes the only lifesaving option. Fortunately, children can benefit from a ventricular assist device (VAD): a medical device designed to assist the heart's left ventricle (drives blood to the body) or the right ventricle (drives blood to the lungs). However, VAD technologies for children significantly lag behind those for adults. While adult devices have been employed in children, the operation of these pumps at off-design conditions increases the potential for irregular blood flow, contributing to blood cell damage (hemolysis) and dangerous clotting (thrombosis). High-risk pediatric patients have severely limited options due to their size and require devices for a range of physiological heterogeneity due to childhood heart disease and the increased cardiovascular demands of physical growth. These challenges elevate the heart failure risk for patients, create substantial treatment obstacles for teams caring for these pediatric patients, and underscore the need for next-generation device innovation. There still remains a substantial unmet clinical need for pediatric cardiovascular blood pumps, and thus the long-term goal of this research is to advance a breakthrough innovation of a high-impact, hybrid- design, magnetically levitated, medical device that uniquely integrates two blood pumps for supporting pediatric patients. This novel device (The Dragon Heart) has only 2 moving parts - an axial pump impeller for the pulmonary circulation and a centrifugal pump impeller for the systemic circulation. As a hybrid dual design, the centrifugal pump rotates around the separate axial pump domain. The device utilizes a magnetic drive system to facilitate a longer operational lifespan and wider clearances inside of the pumps. Wider clearances lower fluid stresses, hence reducing the risk of thrombosis and hemolysis. It will be able to produce continuous or pulsatile flow, and a wireless energy transfer system is implemented to eliminate the abdominal driveline. The device is compact (60mm x 50mm) and delivers physiologic pressures and blood flows for high-risk pediatric patients with varying levels of heart failure, anatomic defects, and size or age constraints. We have generated compelling preliminary data to support the viability of this device design. Our central hypothesis is that this innovative, hybrid integration of an axial flow pump within a centrifugal flow blood pump will successfully provide versatile cardiac support to pediatric patients with heart failure. This hypothesis will be tested in these Aims: 1) establish the optimal axial and centrifugal pump geometries that achieve design requirements through iterative design; 2) characterize the ability of prototypes to attain design criteria by hydraulic, hemolytic, and phantom-MRI flow studies; 3) demonstrate the ability of the Dragon Heart to mechanically support blood flow in an acute animal model. The combined interdisciplinary expertise of our research team places us in an excellent position to further develop and evaluate this innovative technology.